ALMOST a third of 1,684 light and hazardous goods-carrying vehicles stopped by the Vehicle Inspectorate during a one-day nationwide spot-check had serious mechanical defects. Customs and Excise and other enforcement agencies issued 486 prohibition orders on Operation Mermaid day - 7am to 3pm on November 18 - and 261 of the orders were for vehicles to be taken off the road immediately.

The balance of 225 were delayed prohibitions, requiring defects to be fixed within 10 days. There were 37 foreign vehicles in the catch. Brakes, tyres, steering and emissions were the main problem areas, but while examiners were checking on the mechanical condition of vehicles at 88 sites across the country traffic, others were looking at documentation and compliance with construction and use regulations.

The latter checked 1,877 vehicles - 65 of them foreign - and netted 303 offences requiring investigation, issued 31 immediate prohibitions and delivered 353 verbal warnings for minor infringements. Of the 448 UK-registered vehicles weighed, 68 received prohibitions for overloading.

The checks were the fifth run this year of Operation Mermaid, which is co-ordinated by the West Midlands Police and involves 52 police forces as part of an ongoing campaign by the Vehicle Inspectorate and police to improve the safety and mechanical condition of commercial fleets. A new campaign for 1999 is expected to start in February, and like this year's spot checks will target different groups of goods vehicles on each occasion.